To get reactionaries to spawn, try declaring an "establish protectorate" or "conquest" war against a small country and just wait. After a few years, warscore will tick down because you haven't occupied the territories you're claiming and you'll start getting peace offers which will drive up war exhaustion and militancy when you refuse them. Once you get up to militancy 9 or so, you should have a huge reactionary faction, and as long as you stay at war you should be able to do the same thing immediately again after the reactionaries win to get more reactionaries (there will be some risk of jacobins, but as long as you ensure only reactionaries take the capital you'll be fine). After this, just win the war and wait for war exhaustion to go down (using the opportunity to pass a few social reforms will really help if you want to stay an absolute monarchy as people are going to hate you).
You'll also miss out on all the immigration to the Americas, so it will be a bit harder to stay powerful as the game progresses. Reforming into a constitutional monarchy will help a bit.